INOR 380 |
| The ferric-oxy mineral inside a water soluble, protein nanocages, forms by a series of steps that include a peroxo diferric intermediate common to di-iron oxygenases, such as methane monooxygenases. Ligand comparisons in the two di-iron catalytic sites, show different coordination and indicate why Fe remains bound to the catalytic site at the end of the reaction cycle in di-iron oxygenases and is released as product (mineral precursors) in ferritin. Fe binding cooperativity, apparently independent of Fe or O2, may reflect the multiple catalytic sites. Intermediates between diferric oxo/hydroxo mineral precursors, ferric- oxy mineral and dissolved Fe2+ are not known, but the mechanism for dissolving the mineral is: protein cage subdomains, related to protein gated pores in biological membranes, fold to prevent reduction of the ferric mineral by electron donors in solution, such as NADH/FMN. Selective unfolding of ferritin protein pores by low concentrations of solutes, e.g. 1 mM urea or heptapeptides, increases reduction of the mineral and likely mimic biological recovery of mineralized Fe Part support NIH-DK20251. |
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ACS Awards to Inorganic Chemists
8:10 AM-12:50 PM, Monday, April 7, 2008 Morial Convention Center -- La Louisiane, Blrm. C, Oral
Division of Inorganic Chemistry |